Abstract
Inclusion body myositis (IBM) is a refractory muscle disease characterized by inflammatory and degenerative features in myofibers. Macroglossia is common in systemic amyloid light chain amyloidosis; however, no reports have been published on patients with IBM. We encountered a female patient with clinicopathologically defined IBM who exhibited relatively rapid progression of dysphagia, gait disturbance, and macroglossia. Muscle biopsy demonstrated endomysial mononuclear inflammatory infiltrates, fiber necrosis and regeneration with rimmed vacuoles, and sarcoplasmic inclusions of p62. Tongue biopsy demonstrated fiber degeneration with fatty replacement and fibrosis, nonnecrotic fibers surrounded and invaded by mononuclear cells, and sarcoplasmic dotlike inclusions of p62. Based on the parotid gland, lip, and muscle biopsy, she was diagnosed as having IBM with Sjögren's syndrome. She was treated with steroid pulse and intravenous immunoglobulin therapy followed by oral administration of prednisolone, which resulted in temporary clinical improvement. Macroglossia might be an indicator of immunotherapy effectiveness.